def count_clear_or_water(quality, clear, water):
"""
Count clear or water data.
Arguments:
quality: quality band values.
clear: value that represents clear
water: value that represents water
Returns:
int
"""
return count_value(quality, clear) + count_value(quality, water)
def ratio_cloud(quality, fill, cloud):
"""
Calculate the ratio of observations that are cloud.
Args:
quality: 1-d ndarray of quality information, cannot be bitpacked
fill: int value representing fill
cloud: int value representing cloud
Returns:
float
"""
cloud_count = count_value(quality, cloud)
total = count_total(quality, fill)
return cloud_count / total
def ratio_water(quality, clear, water):
"""
Calculate the ratio of observations that are water.
Args:
quality: 1-d ndarray of quality information, cannot be bitpacked
clear: int value representing clear
water: int value representing water
Returns:
float
"""
clear_count = count_clear_or_water(quality, clear, water)
water_count = count_value(quality, water)
return water_count / (clear_count + 0.01)
def ratio_snow(quality, clear, water, snow):
"""Calculate ratio of snow to clear pixels; exclude fill and non-clear data.
Useful for determining ratio of snow:clear pixels.
Arguments:
quality: CFMask quality band values.
clear: value that represents clear
water: value that represents water
snow: value that represents snow
Returns:
float: Value between zero and one indicating amount of
snow-observations.
"""
snowy_count = count_value(quality, snow)
clear_count = count_clear_or_water(quality, clear, water)
return snowy_count / (clear_count + snowy_count + 0.01)